SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c014e46748c8a4ed646b4e34ec7f9b421cdf976a2197d96d5580080997e221c2' 
  AND token = 'd2LScEPKMQplD6WmmPuoYIpF96iBzbcDuvUHItKrD3s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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