SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b86c16e21771537602bb9402c5c22d144313e671449eb726a292c4e6c0edb15' 
  AND token = 'jybzsvaz2Ha+XVehdJ+ZFFINSHqVClv/H4f5+xOje48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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