SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2215e54f840b75e4a3ccb6aba6c1b896594a23d8826137572de0a0b6bf788c8' 
  AND token = 'rLxpLoBuWNTAZXyPJ9DWh59NrV54I6oYN0wO50Pnu5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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