SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c510721a7c2bb2a45f7b4e892acdbc049506ef0bdd07e5a84a2ca9963fd118c' 
  AND token = '2Lny/UnAYwZQAQpSVq+I+RzfyY/BYhbssDIJLPneBSI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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