SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8eb3612b8127dfc4f65313f9ec30707e00b1eb2f4d530cbb3275d86961d411a9' 
  AND token = 'ouPJ9ja6/k5/z9V8P3U81QwUZ3pl1wC/2I4gTGzrAsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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