SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e8670b397ab228cb856be172bcf72e1031d6879748053f96c954be6f7ded6a6' 
  AND token = '1jxjLmJ/OWXAHhcsjv4u5bm4FPeGQrKTzpFJZwcwYKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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