SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '94f0f350ae89c12da5516a36643c90cf31f4688b434269508eb621da56dde231' 
  AND token = 'r4dvCcrzoWHqkAAyazk8namF3doe3RdQteO/k6ZJFXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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