SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c31ac348cdf00306da9332d4be74e9f42467127fbee044c452118e22ed5cfcf' 
  AND token = 'nkV7zbREZcMVtgJhOoCHXhZoB4JnUf1ZDrJwyueOPH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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