SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7876eabd5f9db03d9f218d12457d6b8083e1d51bc162478556c4c91df629c28f' 
  AND token = 'J8hE4RvmwXoLHQLtzRGPaylNwbjwaJqfaIiEnteLp80=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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