SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e875b8c1600ba08983b28dddc867ec747e84652c306e8fd6a316fbec252fc47e' 
  AND token = '57snjHkc5JVfjpwnVEbnzG33xhDtj3ko0pFr7YqpF0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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