SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fe5b5263e90d1338e7d6945cc6f062ab54e08ce50856c0937f1d3ce759e5268' 
  AND token = 'YGLMik6QtW/3CQHf/Xt5aFSwdOtThNqPbgg4mMRTh5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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