SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ec3c154d8129ac833205fc9bc53561d499f7872a0298e6d21dfd5d84cff65eb' 
  AND token = 'zASZg/jMVUVHBnPHtAIvNOS3y4nmZEYPUhK1WT7osoo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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