SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c13c92311c5085dda1b7a2f8433da32046a279b13794e242684f79719c43b65' 
  AND token = '/uUAhWI1kw4FvHXb9XTVDqAbdbU2jSLRiJ/ZtoXHjz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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