SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '294afbe7c94cc838db9a3526105858dc4afdadd156209a93accc1caf08cce9ae' 
  AND token = 'iqIijt7tBtFdpNd2YX4rTfkBYWVwDgI1Hi4w80GqoLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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