SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb1299d63eabedefbb3eee10594ae08ed3cd59810612eeba6443e2630fa26f23' 
  AND token = 'gjbxkHEMLmSsHLgPgGog6T2rplSGbiLFQkyPScKtm+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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