SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90d6d848e9a7d2ff239f0d34dd38550f856a057e89b7f4e73e4fc2bc7c6facc6' 
  AND token = 'OtnXI1St/RWJHKlCpWpcUXssTDq0U4QqrWlCCPyKE2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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