SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4217eeb195c38ea14c8409f5326d80650738d9f78b0ea7da77594057d5507f8' 
  AND token = 'oUDzBuLOWV7eUfh+dCpJqYENv43TXsrrfSBzsWLWVEM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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