SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67e6e08aec15d723ecc99200cd3ab0938b92a43d787ac081719e3fe0b6ecc63c' 
  AND token = 'dolQ689qTksxVqvR1skvcaqa4jkJOeIFXMNDjZpQm74=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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