SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b50cbbedbf491df1b12b952b36d112813f85afe84e7a5475d4c23064a0c3b49' 
  AND token = 'J7SBiZbveXypZ7+GtsvLN/HuWQgFqj3jWJ65E45o0e8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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