SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21312f971e9c77fdd9807b5ada38da06b143825fabbc6ac1b6af654f5b29ecc0' 
  AND token = 'cKgLNqB3qmkCiFA103vopK0zVCRfGwa/Ou+gMGDzUx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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