SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82f80d0a204aa1d4a26355a86c6925f55238257d8af8d49e048fa6e25b6106b1' 
  AND token = 'v3KBsBf9WJ+OWxS3RMZ/pp/wZITirp7Rl2YGYv2fbNU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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