SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdee9a07bd3f1058be133a889ca10f47fa49d8119c3e1d7c3e87c2d8c7ba9ae3' 
  AND token = 'grsfQGlgCMnEIFnAc+/iOudPGSYuHQTA9fOIFLNbhNo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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