SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfab82e06b78e32f619443987f0be6681b531c3820682d0882ed172b4db7013c' 
  AND token = 'pt86PCawzRIA8YNuCIj6YfwHimrbmWgvjoSLKDqnctk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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