SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfdb2fee67da5f9471a84a32aa17acc9a899ddeb5936ca2d62ac52505931880f' 
  AND token = 'HAmlDybhTKxWLMJcQuxbvpR9ZgvlXSbjEyW4OZkwvhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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