SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5973c6589564b9f6b590f8e3b923b8e0167847c99af8d7197fca664b9cceb9eb' 
  AND token = 'FejwfKgp7tcTp3ONIs8CXslPmwicVQOQfAuJyCATkUE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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