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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '347ddeec053e9d740238ab1f95506f02a0dbc2fdf4fad451c250e4bcfcdabdbf' 
  AND token = 'rRTu1wCEmHDUBL7Nn2mypbCIyH2y6YzXCgsHx4Uw+Yo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}