SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fef6f2f2ad83c394e0ba0e47e9afa2ad1b24f5cf4b38b51a894d1d1d80fb35c2' 
  AND token = 'aGU+1HYNbz0rk07mGgNYvfC2ngIBPoY5GwxnVzr/fx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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