SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9148f510c14a105f9710c1fe8aeb6eaff7ad4995327ab59ab2327e8b027de81c' 
  AND token = 'kGK2/qshS+hTopB6EfHeTgnrWuuFpEYMbTgXkYqgMMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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