SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1ffc8beb16956d8c9638bd271bf396f95a07443d9ba5402a05f63696a18ee39' 
  AND token = 'h4nLjtsNlmHtwrYgqS2q4z4FeWxiRTVv6F7xhuIj0RM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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