SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcfd748b14b87069e35d1496726be91285810163abeca635933979b3d65d2194' 
  AND token = '3Ecs1IPLrhvuHlxVfS1vzu93exA/2t3NUuH22Y+Zzcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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