SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65f249faca86798581b50e8098d15295ebaa4aaa28c0259a93093111ed6672c2' 
  AND token = 'mPcyQlQjPuPzJIRiBXfNvSUPgsgscEWQzaFnCrTjg4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}