SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36f46e9beec6dc3a9b42b781455686429a128301160ea4fe91c81ed8abcaf3a4' 
  AND token = 'VRLhxCN15PezEHAnnBYxuuBqSr/bYMFluVmTEqlIXMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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