SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00dbfcadc20b22554ab937a186f63f4b8d366942af96030bf42e9f7604eaffac' 
  AND token = '4BL1DPchY/jgDEbL3ghkN3hluOQ/Kv04Gbr0h6GoGkM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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