SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4e2f3eb968893eb788da4bfa451d1296a22d37d747a83324351c81d0a7aa42d' 
  AND token = 'qUfKmhfpG2hV8Jc/YrkTdP9XMxgBKkRboRAHwjljxR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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