SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f21f42c24c701fe28514d4e89f3b925cc6e566f14618be8861f6b7959020dab5' 
  AND token = 'j7RtsziPxu1N5H8eAxUusl0dhB8gvIKHLsu6Wtd2ngk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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