SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b950fbda35639a58b70c587c0dee242bb53d87827494eecd62676f84b486d05' 
  AND token = 'dMiYvqbMch2VGPH6HfOw2drrA4GHTbUscCjn5ARVccA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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