SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cfb7e23d3917f868b57005006b485b3c2c81002474ed59c8b4e47f744f3c77c' 
  AND token = 'u0p/Ge17rlspXcOUnqpE4dUNAspfalWBAKNPxSCOy00=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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