SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '413d58030a1738ba904c75a79db1f11b3427fef52db2090602e3886480bdff85' 
  AND token = 'IM3s/bn0ATsuJUZHQhXgqZZwtsvd8sUbFsmsrjzksK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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