SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19e7d7c5e7a0a14617b94f447e670680f7843d530e43413468079f3cb3d52b1c' 
  AND token = 'LQRHN+Tayh/0VLxHjRyhFgoAAYnYBf3AhQfVVfPOMGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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