SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dbd480d05a152c4bde82d567dd90f57a46d2e5af2953e1b9bdaccc5c26ef559' 
  AND token = 'YWDX5ntce9noQMDWxFDwbtI+TKfPefotB2gGMXZjz48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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