SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'da8c5eb5ede0277d758a9f2c760728206f6ffe17b4145705be6f47dc4cbf895c' 
  AND token = 'Bb6hoUbQ2hZ8lMREcCF7LOXM1Qpz7NKmxgOMomQHPbk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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