SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '78efad2c49041254098dd6d7547edc132feebf6cf1576281e07bccb01a29f914' 
  AND token = 'Ika7sJL0Ylhlm00gliD2BC+h5R62Nlc1lf2LqSOJPDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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