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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a63bf93a4ceab09e7740349e9a63b3b4fa88dbeee7d7af8689a5213d05b23e4' 
  AND token = 'rbFQ79fRAr3tCfIcnHp4X3BtyDrAR6+G+x/Gj/wvcHc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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