SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7897719aeaf5dfacf6d13bbe88713f72a1e92572bf6d1da7601bed9e6f540c9f' 
  AND token = 'pa+4huiaN/AJ1gn5aOVP7UtYrpH+jsTUpM4fYKGp+co=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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