SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '388f237234a3247a790b24175bc4226e6368e9a072d1f89e3cc4df6ba4d31256' 
  AND token = 'dIrEvYuV8J0Wr2BMV/OVVzJEE63yIB4W0YOq7e0a9Rk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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