SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99d224d72c710195148d202a073cd905d6bc937a4b9f86b286ca418db75d9253' 
  AND token = 'vRx5hnqrs8E+rUP8Duzv4/ZX/PSqozUCkUc8N+fVA44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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