SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0bda286ea084640281c586e8f6e28473cbdf56878c800fb65a78c495ebf7c836' 
  AND token = 'CzGR0+p1acdSS9hiRGCxWgql+ekTrfpRqGekuhmuHDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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