SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f23bb302245558ef3481577755839821b5e11254cf18843089d02f77f29c3ba6' 
  AND token = 'DJRuV7RH5hdHuRN2zb2TFebwZC86NPHsAdDBuC+NqSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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