SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8f2108e54e0af90ba420ad4616474548359780c79ad7a0f11d230783d00f28b5' 
  AND token = 'ela+cbkTxWzM2qWxPPcaH5CJvZt674kjs02kMks8uXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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