SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b93dfe0a1986cc318cf8730efb2fbb4dac75f0425adb0e2fed1c2f4fa498a2bb' 
  AND token = 'cfxqsccx1/gv9ptzMWEEoXagmWd2+r94luiUWhdEWf4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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