SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '05170e76d0f001aec4bb556e88c79a8edd824c2bf68b2d56a74603baf2390a15' 
  AND token = 'kzfV/rklYHGsKGMhnVNK4UFlQakzg+/5KmCTl+amVHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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