SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f9baa696c4647fc9a28531a67f5a328274746f88d5ea9b9200eeaf8e9e9bed5' 
  AND token = 'c5ndY5x0jEk3TePC2x0gFpLtBJIbzJUr8RGByvaGbKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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