SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '271693ff70b8baa270c5ad2f5b32eaeb510011dc6432d91977dc7738c545596a' 
  AND token = 'aPOtlQ5cpTLzGA5XBuB0Z9AoDhb49OgK/Y4Bn+KMB0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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