SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a866afa303a650bac7457d1ea5f8c2b9c35fdd51e4f00ea6e1b3bee2183203fd' 
  AND token = '1kvRFajX27xBLz4q704zm/Dvo/0b3DoyDAykjENQqdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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