SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8aca2155f1abd10422dd4fbcb4d1981509a4c07de4a6641d2f2f5a4ece8f006d' 
  AND token = 'juSuHKPZ8EJIN//OqgSM5yCrlL75tzzLDAxaqun9q4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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