SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5fb6d6db7f0a6b089666373018509987b85cdbd261b166915860fdd06cdbd00' 
  AND token = 'KR3P7BzHIfQR7rLJnf17cEA3JP4h063YKK+iaEZXVcU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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