SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b38241268e1e4ea14c46c486eddf10132c576c96a0916fcc9c76a9f08eb2f8ce' 
  AND token = 'DRKWbF/5HuIrhgevWMvBFmjEMo1WJoxiiTSCVck2PKQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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