SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ab1db3ff686626861ffcbfdef9048952ef69d1c1031f18e131ee73e7e5d585a' 
  AND token = 'iMP117g2M1zvhK25g3+soFKEj22aGUfHWfTZnGIZDmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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