SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '78b3524474d28c15234dfdddbff8fd643334fcfe981e950fd353261a57077803' 
  AND token = 'Ft3grIX1q6RzeMKVHgIS0FvKYqL/A3ybbYcCbS/MUTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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