SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e79e0a7900e2b3ed8918cb360671ab565c540baca98c31d06555934e06183677' 
  AND token = 'hT/nnj8oAXoyz+ISxc2DuxuH+XICuZOc0opvnSAgJYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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