SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3211aae32789669c8546eeb4aafafcab0dd480f916da346ed622fb427bc38271' 
  AND token = 'mLSCRoxKN10LvWxxaIaLKEELeoMak0ZSxQppadFtRSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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