SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89523b05313d664f34414f75759d2a84baca5b5a981a6e39cc8c2237e8f53538' 
  AND token = 'axr4XJHbgzUxs7CBi1GqcB97alTKWtjNZpt/lz5q+uQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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