SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18f795d6f827d5dbddafe1833177a4d8980fbb5b93883422291e75a6341a1b06' 
  AND token = 'PrL2WU6dlv+lI8LP54WABJJHBcgqdqz1zcEli7VzFJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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