SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc5c6481df75276dbe2548aca696a8717fb57f75a5cd2143e45735730c510730' 
  AND token = 'wqWGhuhWLcrMn7rCCki9HrNbDFigtRbWiywHfdm/oBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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