SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70404b38e18675fac0dac97103592c0724170875dba702927bcfcee583c4aa56' 
  AND token = '1zARnwdcY/BpUb+g7OsRJLYwGePW5hQYV4roip1Vv7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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