SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adad7e96d67af8f1fef8aec0df3fadc610752b74b54a4b060034ff1d97719bfe' 
  AND token = '5hzrJxYkcsjqsHWrLP4QZJE/tQ0fXjhDJu+ALqqmn0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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