SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13f627fdcdc74349f29edc180e79ad2f87bee23f1b05d675141c40d98c3e87e4' 
  AND token = 'mJzU3a46//fT79are+IT++sLNl88nFmV/MMlgD90nPM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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