SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96f72ac375debd2d3969e072569c058ca689a6c3a5ed135bbb7b98fce03bac94' 
  AND token = 'qKMylzgAMPukrQMVLAemV71CywcMuisoiZ2Al642nrc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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