SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1908a50fca8c7422f851b7f8d131772c542a1726b9b67e7e9be80d654eec444' 
  AND token = 'wHY4z1yqxur1g6Q4SG5j2VUJtWoJ7z+JupbC+bcLWrg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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