SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bcc77e943c3ffc2b4a80b158b1a0370d7f692e6a7e45f0d41835b9ffd4f66b42' 
  AND token = 'MGdBcgDQkfzzzv3Lg/YHLzLdrCZAzqlOXVbZRR8mTtM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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