SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfdcf8930b375be441e5425da94a4730e0b74054d8b1e1c87fc1d0d857976a30' 
  AND token = 'jqbs48nGXO3kOnzvVBsFdxCvZpQ+5l/dxNgjOhIVI/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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