SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b865a5b200d72c429aed68e618b000a53cb085d7a16d02b3bf1a1ec267f9739' 
  AND token = 'WmVVK+VP4Y9zJkcX3ZrqavfE7xjIC8BKAzsK4z9KQpw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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