SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91c680332a6180520ddcaa2cc69819bb11592df8143a2b322ed5c78dfa205345' 
  AND token = 'UhHF/OUdDrxQWRH+qa6rRRJz8lZEFNvDzzDSVVSRjjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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