SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b37b2ff1a15dbee63574cf76a9410d4fd37dbddf894c1b5f29dcca20589e6be' 
  AND token = 'oES7GZuWHulaUIh3cEgJQ2in2k/spK/Upov3JVVZFWI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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