SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3289781c5ab608578546aa9dec5e1b1f6464cc62051fdfa6f84ab8a85ff11d61' 
  AND token = 'wyDQ/VG7pcYZmlMAvfeiLZuv4w7/6kUCSHj4GX3+3nw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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