SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a7744ea43c787b34be976939f4ee28e92f12af83d206394faa5399039e5efcd' 
  AND token = 'PY3uv/qb8m3H/mbcphosxwug5ZcoWZUvMV4WmAlFNBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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