SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e714fef4dce9e31c6565ebfa212ca0d4c1ba470eb8224d90674e0b54ba581cd2' 
  AND token = 'CvhIz9/TH9JfpPkux0/Ivn6ToV4oRm5Gv1YPxiZyVGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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