SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15156c0d6bdddb5e2086ba9b8ec15db4d56a928474c56c6a16d67f1944c36e01' 
  AND token = 'S5LnU5jtmuhA/RWTa2QOJZTjDNpecJcCehZpkKv+Qms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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