SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abf799c1c04b43cd382cccc746a3ab8ebf957c00595be3685fc6848200fc301d' 
  AND token = 'kdGQD+InbcpRbDh/vySK3JB6Tn91cGWjco5kONWZ/08=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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