SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '819724a9e3505d4bd1937cea5d6ff49f36796f20168f8630d57b29be25e56b26' 
  AND token = 'KvsZ/qaFdgXqNHFiMbXVm2uJS5l8gh0MQX5WzLRyscQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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