SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e603fc5f76536af1ea36a0a17616e2165240ca7aa80276412967130daaf42f60' 
  AND token = 'mVb5a75zMRs7MBJki86sUw8V8PRmjf0SyAAVnuDJAzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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