SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f42b32ec83be235214e683d72913772f12ab75501d34bef2bd692765e6b38b9' 
  AND token = 'XHeAm5E7KyWAw0cpIAMZujJBzUGGvJ6eG0g/fmw8vfo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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