SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96149486e16f283fd884994396191b0373118af6586a4b1ceaacda779e4fc44d' 
  AND token = 'mKDYZ5xtstgESJLQboW4IOedQhFJlR3TVbLppZ1zh7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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