SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6ad612934c93ea047873fcf5dbfc9bcc70a1b0a5749678ab50c75ff99a6d9f5f' 
  AND token = 'sODMdd2sJslg0HTVgycRECSSvAdZ2aDpU2iDVsgbCOU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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