SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74c8d4c984ae29c8022aebd4300b3ff04c870a0801dce42725d0ed064583c9a4' 
  AND token = 'tQn3xM610rZSpt7HhWXNoVVFWhsZ6HTSPPH/qmUpdRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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