SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7b775eb34659f856c2509cd03067e4bfdc0514a0ffab7bbaea346142ecb6f69' 
  AND token = 'AQnIDwhJH+iV268jLvOvIbA5xCv5V2SLlcr6UjvpZhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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