SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f050acf35c4a247a74ec01a16642eb13fc4dacea5a5a174fd2a4a351618e5057' 
  AND token = '5STpPNBnnobfH3S+CsgirDo41LrLZrbyOkEtIf0WoLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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