SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1d4c65d1ef421c42026eaf550c7db08e1939719da010287032c9a6bf968f0be' 
  AND token = 'uFzAJ6ED5y25kDCjPz15LxwGAfIVF0uCmQE0kcbyRw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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