SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2842434ccbe42a1e54c65d87a77008722891d5256035d0057be7be8e119d812c' 
  AND token = 'W+FQzws7knMFjqc18hSdif0d/hbKsXj/vJj+XWsD1UQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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