SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbe4e7a9135e6c2b5569399bc746873b7dbe71ecdf5207a4ff328c981219f880' 
  AND token = 'shmPZcfjmLjlqgnFkzFET2DgMkV7jsyr8YY/IHYvuOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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