SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1eb578c6393a638cd326b7b0f938a4263eda0f7c0e3c239f544aa4855e19763' 
  AND token = '1Izhk9Y6GTbQI+LlbWehDza7+GOwJLhQgH6oZSSPgRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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