SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '825050a7870b07334574e25458caf8c577f3024423edf543f43dc7ca24c42ca6' 
  AND token = 'VSsBEbBRt/9rAOIcPBRfwYynCiFnzR42843q+npMBTc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}