SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6297910dda3ed08ac3866bf71c1ca539e7403dd281b9172c1ef7590f8c9e3d2d' 
  AND token = 'TGe5uJHVD0B3hvTJoydzjKog/4wXNCPtSQDDq9WUWwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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