SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40a564fa80d32cd3719c850e46c10756485050713105b9b39f6cf1facdf0c111' 
  AND token = 'uEGY7JRnSNczd5HixnVlto3rl2FoRVzsE7OE0Qq0hdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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