SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3936e64ff86ffcd511cff5d4083cd135c6035d439d735e907979b10ad5fd83d1' 
  AND token = 'd0+w0XCctvMJq+2YbBoveMwDC8wK+LaZigdgCweMoVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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