SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fc2b243d4235b3fe737450cf125a13b4e05a6ef119425bdbcd0d844930f6834' 
  AND token = '5/vpZ2F6XnCGPTj/Imo/8r6C9SSkzPtsnZS9QwY0KvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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