SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffee4e6ebf6fea6e1d5fd15b5a5ea56d26296ae06995e49e9de0d0a898d638f9' 
  AND token = 'R2Dp46PxzZzgVgzmQNlPwC8Cvyiq8HVwchGbMx//LRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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