SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c0948e1609efea15562fd77824d4140004dfed1d0a681b4792430220f65c866' 
  AND token = 'ueD8fYa76LSkqon+IfpFHnl9qFvxGnNVhrEPLgTq4b0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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