SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '412fc21abb448c85bb4f28abcc7607df6d6aa67f32f557a412956993b5a3bd7e' 
  AND token = 'KVAh93DuwsnH/ysAFBCtduC+UP5R0g5W9cjK4bQRlV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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