SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76173dda725ec786841c1dbad018cb197060e22f016793bb844b9fbbe20fab01' 
  AND token = 'Lq1b8aDdNO/qMAmYFVFD2JPIupXAMsVCwN1hoG9bpd0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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