SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e12c3657739970f2d436ea0806659789daa7a2acbb71303aafe326d26e46d6f' 
  AND token = '4GGVa0+JNAr9NzMIPoP8o5IuoznJlRmvp3+x7G+2JmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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