SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88e47a3f44f29afbc69db2e4f6b88fd1f51ba618d4528bf97b61523d71f87d62' 
  AND token = 'I1o7jAh/JrxLT3JJBzzLRLjapXAHuqWtd4KeEHJZLTE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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