SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '461ab49a729e0002cd8a7f797dfd70b2e628b37afbf99c750c3fd32238b6c55c' 
  AND token = 'BGBVnr/owEpzRp4bDGCm+UsBrSzs6/LGx8/HtDMFSiQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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