SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f7b074e07e62b472ecc1c2aaa8d84f0a1e368de8b8d96392be87489d403f240' 
  AND token = 'VtMsGgJHkWLewJG2nPYBVSTJtuGwClpBE7ZP+faQcls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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